1. Field of the Invention
The present invention relates to a light source driving device, an optical scanning device, and an image forming apparatus. The present invention particularly relates to a light source driving device driving a plurality of light sources, an optical scanning device including the light source driving device, and an image forming apparatus including the optical scanning device.
2. Description of the Related Art
There has been a demand in image forming apparatuses, such as laser printers and digital copiers, to improve the printing speed (fast printing) and the writing density (high image quality). To fulfill such a demand, methods have been developed that employ a multi-beam light source capable of emitting a plurality of light beams simultaneously and scanning a broader area of a target surface with those light beams at one time.
Such a multi-beam light source includes a plurality of light emitting sections arranged at predetermined small intervals in a staggered manner in a main-scanning direction to realize scanning lines that are arranged at the predetermined small intervals. In this configuration, however, it becomes necessary to control the timing of light emission for each light emitting section so as to align write start positions on the respective scanning lines.
For example, Japanese Patent Application Laid-open No. 2003-276234 discloses an image forming apparatus including control means that controls lighting of a plurality of light emitting sections of light source means. In this image forming apparatus, the lighting timing for at least one light emitting section of the light source means is determined based on an image clock generated in synchronization with a detection signal from synchronization detecting means, and the lighting timing for the other light emitting sections is determined by changing the count value of the image clock.
The control means disclosed in Japanese Patent Application Laid-open No. 2003-276234, however, suffers from poor versatility because of limitations on the main-scanning direction and the structure of an optical system. To adapt such control means to other image forming apparatus having at least one different feature regarding the main scanning direction and the structure of the optical system, the circuitry needs to be changed according to the main scanning direction and the structure of the optical system.